The invention relates to an intake system for a multi-cylinder internal-combustion engine, preferably of a passenger car, that for each cylinder has two intake valves respectively and two intake ducts that are separated at least in sections, the intake ducts that form the component of a cylinder head being arranged on a joint plane extending vertically to a cylinder bore axis and being connected to the intake system.
In the case of a known intake system (EP-PS 00 54 964) of the initially mentioned type, the intake ducts extend in the cylinder head and the ducts in the suction pipe that are connected to them extend vertically with respect to the longitudinal center plane of the internal-combustion engine. This construction makes the designing of the suction pipe difficult in the case of narrow cylinder distances of internal-combustion engines or in the case of internal-combustion engines having, for example, V-shaped banks of cylinders. In addition, the different lengths of the ducts are hard to implement in the suction pipe.
It is an objective of the invention to provide an intake system that is held at an internal-combustion engine and that, while functioning well, has dimensions that are advantageous with respect to space.
This objective is achieved according to the invention by providing pipe body pieces for each cylinder which connect respective pairs of inlet ducts at the engine cylinder head with an inlet manifold system, with the ducts curved and interlaced with one another in the pipe body pieces so that the duct ends opposite the cylinder head are disposed adjacent one another in a connecting plane for connecting to the manifold system.
In preferred embodiments the pipe body pieces are identical to one another and are connected by screws to a common manifold member for a bank of engine cylinders.
The main advantages achieved by means of the invention are that by means of the interlaced course of the ducts in the pipe body piece, the intake system--seen in longitudinal direction of the internal-combustion engine--required little space which is important particularly for internal-combustion engines having cylinder banks that extend in a V-shape. The separate pipe body pieces simplifies the manufacturing of the intake system. The ducts of the intake system manifold that have a varying length can be integrated into the intake system in a simple way.
The intake system of the invention is especially suitable for internal-combustion engines having V-shaped banks of cylinders that are installed transversely in the front end of a passenger car, a significant partial area of the intake system extending adjacent to a cap of the rear bank of cylinders. As a result, the space between the internal-combustion engine and the body of a passenger car is utilized well. In addition, the passage ducts in the intake system ensure that spark plugs of the internal-combustion engine are accessible without demounting the intake system. Finally, the vibration-neutralized bearing of the intake system contributes to the nose reduction of the internal-combustion engine.